Glossary of Building Terms

The following is a reference list of common building terms used in the construction industry and a simple explanation of each.


AG LINE – A perforated pipe (usually covered with a geo-textile fabric) laid behind retaining walls and other areas to catch seeping stormwater.

ARCHITRAVE – moulding surrounding a door or window opening to cover the join between the frame and the wall finish.

BAGGING – A method of finishing brickwork involving the application of a thin mortar slurry using a hessian bag or sponge. Can be painted over or left to fade in an oxide finish. Usually completed by the bricklayer. Bagging varies in texture & colour greatly and is not uniform like render.

BALUSTRADE – A series of vertical members supporting a handrail of a stair, landing, platform or bridge.

BEARER – A sub-floor structural timber member which supports the floor joists.

BRICK VENEER – A method of construction in which a single leaf of non-load bearing wall of brickwork is tied to a timber or metal framed load bearing structure to form the external enclosure.

CEMENT – A finely ground inorganic powder that, mixed with water, binds an aggregate / sand mixture into a hard concrete or mortar within a few days.

CONCRETE – A conglomerated artificial stone made by mixing in specified proportions cement, water and aggregates and pouring the mixture into prepared forms to set and harden.

CORNICE – A moulding placed at the junction between a wall and ceiling.

DADO – The lower portion of a wall above the skirting when finished in contrast to the remainder of the wall e.g. with wood paneling.

DAMP-PROOF COURSE (DPC) – A continuous layer of an impervious material placed in a masonry wall or between a floor and wall to prevent the upward or downward migration of moisture.

EAVES – The lower part of a roof that overhangs the walls.

FASCIA – A metal profile, which is fixed to the lower ends of rafters and usually supports the guttering.

FINIAL – A decorative fitting used at the junction of ridges and hips and at the top of conical, pyramid or domed roofs.

FOOTING – That part of a construction designed to transfer loads to the supporting foundation, usually constructed of reinforced concrete to support base brickwork.

FOUNDATION – The natural or built-up formation of soil, sub-soil or rock upon which a building or structure is supported.

FURRING CHANNEL – Battens fixed to the underside of trusses, rafters or ceiling joists to produce an even level ceiling.

GABLE – The vertical triangular end of a building with a pitched roof, between the rafters from eaves level to the apex (ridge). It may be formed in brickwork or timber framed and clad with weatherboards.

GAUGE – An indicating device usually in brickwork setting out the number of bricks to a certain measurement. E.g. 7 brick courses per 600mm in height. This gauge is adjusted to suit the brick and the site conditions.

GIRDER TRUSS – A truss that runs in the opposite direction to other trusses and has brackets (shoes) to carry and support the other trusses. The girder truss is often a double truss, made of hardwood in part or has bigger elements than other trusses.

GOING – In a stair the horizontal distance from the face of one riser to that of the next.

HANGING BEAM – A beam above the ceiling used to support ceiling joists.

HEAD – The upper horizontal member at the top of an opening or frame.

HEADER – A brick laid with its greatest dimension across a wall usually used to tie two skins together or under a door sill or window.

HEARTH – The floor of a fireplace and immediately adjacent area.

HERRINGBONE BOND – A brick bond giving a diagonal pattern in the form of a series of vees or inverted vees.

HIP – The meeting line of two inclined surfaces.

HIP ROOF – A roof which is pyramidal in shape with sloping surfaces and level edges all round.

HOOP IRON STRAP – A strip of thin steel (usually about 25mm wide) which is usually built into brickwork or nailed to frames as a tie-down for wind.

IN-FILL CONCRETE SLAB – A concrete slab poured between base brick walls laid on concrete footings. An in-fill slab is supported by formwork or compacted filling.

JOIST – A timber or steel beam supported by a bearer which the flooring is fixed directly to.

KING POST – A vertical member which connects the ridge and beam of a roof.

LAMINATE – A product made by bonding together two or more layers.

MELAMINE LAMINATE – A laminate manufactured from layers of paper, textile, plastic, wood or wood veneer compressed at high temperature and ser in melamine plastic. Often used as shelving in robes or kitchens.

LINTEL – A horizontal supporting member spanning over a window or door opening. A “galintel” is a steel lintel used to support brickwork over an opening.

MORTAR – A mixing of bush sand (white or yellow), cement (grey or off-white) and water for brickwork. Usually at the rate of 6 part sand to one part cement (by volume) and if required one part lime. Can have a flush, raked or round finish.

NEWEL POST – A post at the top or bottom of a stair flight to support the handrail and/or winders in the stair treads.

NOGGING – A horizontal timber member fixed between joists or trusses to provide stiffening or to support ceiling lining.

NOMINAL SIZE – The size of a timber that is used as a convenient description but not an exact size. Also usually before the timber is dressed.

PARAPET – A low wall to protect the edge of a roof, balcony or terrace. Many shops have a parapet at the front of the building for signage.

PARTICLE BOARD – A flat floor sheeting of good dimensional stability made from wood flakes and synthetic resin / binder under heat and pressure. Can be produced with decorative elements for joinery work.

PELMET – A built-in head to a window to conceal the curtain rod or to a sliding door to conceal the tracks. Usually made of wood.

PERP – A vertical joint in masonry construction.

PITCH ROOF – The ratio of the height to span, usually measured in degrees.

PICTURE RAIL – A wooden or plaster moulding fixed to a wall at or above door height for hanging pictures or for decorative purposes.

PLYWOOD – Sheeting made from thin layers of veneer at right angles to each other and bonded together under heat and pressure. Can be used as flooring, wall sheeting, bracing and formwork.

POINTING – The completion of jointing between ridge or hip tiles with a matching colour after bedding of tiles or troweling of mortar into joints after bricks have been laid to touch up.

ACROW PROP – A strut which is light enough to be man-handled, often adjustable in length and used in scaffolding or to support beams temporarily.

QUAD MOULDING – A moulding with a cross-section of a quadrant of a circle used to cover joints often in eaves or at junctions of walls and/or ceilings.

RAFTER – A sloping member in a roof providing the principal structural support for the roofing material.

RAFTER (COMMON) – A rafter spanning the full distance from the eaves to the ridge.

RAFTER (CRIPPLE) – A rafter connecting a hip and a valley.

RAFTER (GABLE) – A common rafter at the end of a pitched roof.

RAFTER (HIP) – A rafter forming the hip at the external line of intersection of two roof surfaces. Jack rafters meet against it.

RAFTER (JACK) – A rafter between a ridge and a valley or a hip rafter and the eave.

RAKED JOINT – A brick joint raked out by the bricklayer for a key for plaster or as a decorative finish.

RENDER – The covering of a brick wall with one or more coats of cement mortar consisting of Sydney Sand, cement and plasterers clay.

RIDGE – The highest part (apex) of a roof, which is usually a horizontal line.

RISER – The vertical face of a step in a stair flight.

SCISSOR TRUSS – A truss or strut with a sloping bottom chord to produce a raked ceiling at a cheaper cost than rafters.

SCOTIA – A concave moulding.

SEASONING – The elimination of excess moisture from timber by air or kiln drying.

SHIPLAP – Timber boards that are edge dressed and rebated so that the edges of each board lap over the edges of the adjacent boards.

SHORING – The temporary or permanent support of an existing building, often due to demolition or of footing excavation to prevent collapse.

SKEW NAILING – The driving of nails at an oblique angle often in different directions to improve the strength of a joint of fixing.

SKIRTING – A wooden board fixed to the bottom of a wall at the junction of the floor to prevent damage to the wall or to conceal small gaps.

SLIP JOINT – A joint designed to allow movement between two members usually in the form of two layers of sheet metal with grease installed on top of a brick wall prior to installation of a concrete slab.

SOFFIT – The underside of a slab or eave.

SOLDIER COURSE – A course of brickwork laid on its end.

SPROCKET – A framing timber used in eaves construction.

STRETCHER BOND – The most common masonry bond in Australia in which all bricks are laid with half overlaps and not using half bricks or cross bonds.

STUCCO – Traditionally an external render to provide a decorative finish but now generally referred to as a fibro wall sheet with a decorative finish.

TERRAZZO – A material consisting of irregular marble or stone fragments set in a matrix of cement and mechanically abraded and polished after casting to produce a smooth hard surface.

THRESHOLD – The step or sill at an external door of usually timber tile or brickwork.

TOUGHENED GLASS – Glass made by rapidly cooling the glass to make it shatter into small pieces when broken for safety, It usually cannot be cut and needs to be made to order to size. It is unlike laminated glass which is made from layers of glass with silicon between to crack only when broken for safety and can easily be cut on site.

TRIMMER – A timber member fixed between joists or trusses to provide stiffening or to support ceiling lining.

UNDERPINNING – The construction of new footings or concrete piers under an existing footing to prevent its collapse or failure.

VALLEY – The meeting line of two inclined roof surfaces at a re-entrant angle.

WEEP HOLES – Vertical joints or perpends in brickwork left open above the flashing line to allow water from behind the wall to escape.

WINDERS – Wedge shaped treads in a staircase landing.

Z-PURLIN – A metal purlin with a cross section in the shape of the letter Z.


ABSORPTION TRENCH – A trench, pit or well excavated from permeable ground filled with broken stone, bricks or large granular materials and covered with earth to dispose of the discharge from a septic tank, sullage system or stormwater by absorption into the ground. Also called ABSORPTION PIT, ABSORPTION WELL OR SOAKAWAY.

GULLY TRAP (GT) – An assembly in a sanitary drainage system, consisting of a trap and other fittings. Also called GULLY.

FLOOR WASTE GULLY – A disconnector gully with a floor grate or waste outlet fitting located inside the building and, where required, with provision for the connection of waste pipes from sanitary fixtures.

INVERT – The lowest point of the internal surface of a pipe or channel at any cross-section.

JUNCTION (PIPE) – A pipe fitting incorporating one or more branched.

MANHOLE – A large chamber or opening on a drain, sewer or equipment to permit access for inspection, testing or clearance if obstruction.

STACK – A vertical sanitary drainage pipe, including offsets, which extends more than one storey in height.

SULLAGE – Domestic waste water other than from soil fixtures.

SUMP – A pit at or below the lowest point of a structure to collect unwanted water and facilitate its removal, usually by means if a SUMP PUMP. Also called DRAIN PIT.

TRAP – a) A fitting usually in the shape of the letter P or S which retains water to form a “water seal” so as to prevent the passage if gases or foul air into the building. b) A fitting for the interception of silt, acids, grease, oils or fats.

BOUNDARY TRAP – A trap in the property service drain, usually near the boundary if a property and below the lowest inlet, to prevent the entry of air or gases from the sewer into property service drain. Also called INTERCEPTOR TRAP.

GREASE TRAP – A device in the shape if a box with baffle plates to slow the flow of liquid waste and prevent the passage if greasy substance into the drainage system. Also called GREASE INTERCEPTOR TRAP.

P-TRAP – A trap in which the inlet leg is vertical and the outer leg inclined below the horizontal to specified limits, with or without inspection opening at the lowest point.

S-TRAP – A trap in which the outer leg is vertical and parallel with the inlet leg, with or without inspection opening at the lowest point.

SILT TRAP – A trap containing a removable container for the collection if silt, sand or grit.

VALVE – A device for the control of liquid or gas flow, having an aperture which can be wholly or partially closed by a plate, disc, door, gate, piston, plug ball r the flexing if a diaphragm.

BALL VALVE – A valve having a turning ball with a port or ports to control the flow of fluid.

FLOAT VALVE – A valve actuated by a float (floating ball) to control the flow of liquid, used in tanks or cisterns to maintain a minimum water level. Also referred to as FLOATING BALL VALVE.

FLUSH VALVE – A control devise for water flow at mains pressure to a WC pan; used instead of a cistern.

GATE VALVE – A water control valve which closes like a sliding gate over an opening.

MIXING VALVE – A valve which is designed to mix separate supplies of hot and cold water and direct the maximum.

NON-RETURN VALVE- A valve which prevents the reversals of flow by means of a flap or mechanism. Alco call CHECK VALVE.

PRESSURE REDUCING VALVE – A valve designed to reduce or limit the pressure of a fluid to a predetermined valve in the downstream side. Also called PRESSURE LIMITING VALVE.

PRESSURE RELIEF VALVE – A spring-loaded or weight-controlled automatic valve to limit the build-up of pressure in pipe work, fittings or vessels by discharging excessive pressure to the atmosphere.

SAFETY VALVE – A pressure-relief valve for a boiler or unfired pressure vessel.

STOP VALVE – A valve, such as a gate valve, which can be operated to stop flow in a pipeline. Also known as ISOLATING VALVE.

TEMPERATURE RELIEF – A temperature activated valve to relieve excess pressure in water heaters in the event of a thermostat failure and overheating.

VENT (VENT PIPE) – A pipe provided to limit pressure fluctuations within a discharge pipe system by the induction or discharge of air and/or to facilitate the discharge of gases.

TRAP VENT – A vent pipe from an individual trap to the open air or to a main or branch vent pipe, for the prevention of loss of water seal in the trap. Also called ANTI-SIPHONAGE VENT or BACK VENT.